LiFePo4 cell types

[Gregb]

I have a 24V 10ah LiFePO4 (at least that is what the retailer claimed) battery from an unknown chinese manufacturer. It is very poorly built (the "BMS" boards being hand cut with snips I think) although in a very fancy case. The cells are 260x70x5 mm in a silver wrapping. There are no markings whatsoever on them. The case, also unbranded, has a series of LEDs which are supposed to indicate the state of charge which is a joke because you still get one lit with only 12V !!!! Can anybody tell me what type these are called and whether replacements are available and from whom? One is swollen but still appears to be alive.
Thanks
Greg

 

[amberwolf]

I think you're gonna need to upload some good pictures for us to know what they are first.

The cells sound about as big as Headways, if I'm thinking correctly. But there are probably a number of cell types about that size, including (I think) PSI and LifeBatt. Probably others.

 

[dnmun]

pictures, plus measure the voltage on each pouch. how many pouches/cell?

 

[Gregb]

picture as requested cell voltage are between 3.34 and 3.42 on my auto ranging DMM on OC but the new cellLog returns different values. which would you believe ?? Does it provide a load of some type? doesn't look big enuf...

Looks like I can answer that. I appear to have a stuffed cell. on OC it shows 3.34v but on any sort of load shows 0v

 

[Jeremy Harris]

Those look like LiFePO4 pouch cells, probably OK for around 2 to 3 C discharge rate.

My guess is that the problems you're having stem from the BMS, the voltages you're seeing on the cells look to be in the right ballpark.

Unfortunately, there are dozens of manufacturers of cells in China and we only get to see samples of a few of them, so it's hard to be definitive about your pack.

Your main problem is going to be getting support, but I guess you already know that. The swollen cell maybe effectively dead, which renders the whole pack dead unless you can either get an identical replacement cell or find a way to resurrect it (it is possible to de-puff cells, Aussiejester has posted a video here on how to do it).

Jeremy

 

[dnmun]

if you look closely at the positive electrode tab, you may see where the tab has fractured and separated about 1/2mm above the point where the tab exits the mylar.

ping charges $25 each for those 10Ah pouches.

where are you located, did you measure any of the other pouches?

i think once you look you will find that other pouches have the same problem but have not completely separated.

i have a 48V pack with those pouches and already it has 5 with broken tabs.

 

[amberwolf]

Ooops...sorry I misread the dimensions of the cell you'd posted, and somehow thought they were cylindrical, so ignore what I posted. Sorry bout that.